It is desirable that such a cartonizer be adjustable to the effect that the cartonizer can handle different sizes of cartons and articles, for example, such that during one period of time large size units can be handled, followed by a period of handling small size units. Here the carton line sets a certain dimensioning limit, namely, with respect to a distance between the consecutive units. The carton line can be designed to handle carton members of a given maximum width, and it is then possible to use the carton line also for handling carton members of smaller widths, but what cannot be changed is the pitch of the carton line. The units themselves may be narrower than those having a maximum width, but the distance between their centers or, for that matter, between their front or rear ends will have to be the same as for units of the maximum width. It will be very complicated and expensive to make the carton line adaptable in this respect.
Particularly in connection with cartonizers designed for dynamic transfer of the articles into the carton members that is, during co-motion of the trays and the cartons, it is necessary to make use of the exact pitch as far as the trays on the feeding conveyor are concerned, such that, in the loading station, a tray can be aligned with a carton member almost before or immediately after the article on the preceding tray is laterally transferred into its associated carton member.
Conventionally, this has given rise to serious problems. It is no problem to provide the feeding conveyor with the article trays having a relevant width for the articles to be packed, as this will only be a question of replacing one set of trays with another set of broader or narrower trays, but for trays narrower than the maximum width, there will occur a certain spacing between the edges of the consecutive trays, and such spacing is highly inconvenient for a safe operation of the feeding station. In the feeding station, it is imperative that the articles can be placed neatly in the trays with a minimum of attention and, particularly, in connection with manual filling of the trays, it may well happen that the operator places an article in a tray not fully or not all centered therein, whereafter it should be relatively easy to correct the positioning of the article by a simply push on the article. When the trays are of the maximum width, the tray edges will be closely juxtaposed, for example, one tray will be followed practically immediately by another tray, and the operator can easily secure a correct positioning of the articles on the trays. This becomes more difficult when narrower trays with a mutual distance are used, and, from practical experience, there are many examples of operators having filled articles down into the open spaces between two consecutive trays resulting in sever operational disturbances. On this background, it is a common practice that the empty spaces between trays, narrower than the maximum width, are held covered by plate elements located in the top level of the trays, such that the operator can not loose any article, but rather easily scrape a misplaced article into the relevant tray. However, these added plate elements exhibit some problems of their own, mainly, with respect to the costs of their presence and with respect to their driving through the entire conveyor system.